Starting device for mercury vapor apparatus.



No. 887,660. PATENTED MAY 12, 1908. O. 0. KRUH. STARTING DEVICE FOR MERCURY VAPOR APPARATUS.

APPLICATION FILED OCT. 14, 1807.

Fig. 2.

Inventor j 2/ Osias O. Kruh,

% M a by fitt'g.

' the coil.

UNITED STATES PATENT OFFICE;

OSIAS 0'. mm, or SCHENECTADY, NEW YORK, ASSIGNO'R TO GENERAL ELEcTRIccOMPANY,

-- A CORPORATION OF NEW YORK. I

STARTING DEVICE FOR MERCURY VAPOR APPARATUS.

Specification of-Letters Patent.

Yatented Mayv 12, 19Q8.

Application filed October 1.4, 1907. Serial No. 397,270.

To alt whom it may concern:-

Be 1t known that I, OSIAS O. Knun, a subject of the Emperor bf Austria-Hungary,-re-

siding at Schenectady, county of Schencc tad'y, State of New York, have invented certain new and useful Improvements in Starting Devices for Mercury Vapor-Apparatus,'

alternating or direct, and the like, and comprises certain im rovements in that type of starting device w ierein a heating conductor is arranged in proximity to one of the electrodes and acts by reason of certain rays or emanations from the conductor to initiate the main arcs.

The featuresof novelty which characterize my invention are pointed out in the appended claims.

The invention itself, as embodied in practice, will be better understood by reference to the following description taken in connection with the accompanying drawing, which shows, by way of illustration, certain applications of my invention.

In thedrawings Figure 1 shows a mercury arc rectifier system embodying my invention, while Figs. 2 and 3 represent modifications.

In the particular arrangement shown in Fig. 1', the rectifier which I have chosen to illustrate my invention is of the high potential constant current type. The source of current for this rectifier may be the usual constant current transformer, such as I have indicated diagrammatically at 1. This transformer has relatively movable coils in order to'secure the desired constant current regulation in the secondary circuit. The

primary is indicated at 2 and the secondary at 3. From this secondary extend three conductors of which those numbered 4 and 5 are connected to the outside terminals of the coil, while the third conductor 6 is' connected at or near the middle or electrical center of The rectifier tube with which these conductors are associated indicated at 7, and is of a general form similar to those now in common use. It is provided with outwardly and upwardly extending arms 8 and 9 containing at their upper ends the usual anodes 10 and 11. In the bottom portion'of the tube is a body of mercury 12 constituting the cathode. For'all of these electrodes suitable leading-in wires or conductors are provided.

In order to start the a paratusinto oper-. ation I make use of a coi or filament 13 arranged in proximit to the cathode 12 and connected by suitable leading-in wires with an appropriate source of current, such, for exam le, as a small step-down transformer 14. f desired, I, of course, may use a suitable source of direct current. In either event the wire or filament 13 is intended to be heated to a moderate degree of luminosity and when thus heated it gives off certain rays or emanations which so effect the surface of the cathode 12 as to initiate the mercury arcs and so set the rectifier into operation. The rays or emanations from the wire appear to be much more powerful if the wire has a surface of some suitable oxid, such as thorium oxid, barium oxid, or the like. The wire 13 may be of any suitable metal such for example as platinum, and, if the coating is to be, for example, barium oxid, this coat ing may be produced by di ping the wire into a solution of barium by rate or nitrate,

drying, and then decom osing, the coating in a Bunsen flame or the ike so as to leave a residue of barium oxid; This operation may be repeated at number of times, if desired. I may also use a wire of the metal itself, such as thorium and oxidize its surface as by heating in air; Where such an oxid coated wire is used in a mercury vapor device, it has been found that there is a tendency for the oxid to separate from the wire and this action is probably largely hastened by the scouring effect of mercury particles traversing the mercury va )oi' tube. To prevent this, I provide a shiehl such as 15 of glass or of metal located directly over the filament 13. This prewnts any drops of mercury falling down the tube from coming into. contact.

As recti- I nder these circumstances it is evident. that arcs into Operation.

(- helix,

- at such a distance from t form of a tube en at both ends, completely surrounds t e filament 16, and protects it from any possible mechanlcal in ury due to the vapor last from the cathode 17 or from mercury articles otherwise moved u or down in t e'container or tube 18.

the protecting shield or screen 16 must be of m iterial which. is pervious to the rays or elnanations which exercise a starting action upon the cathode 17 and set the mercury I have found that a material SllltitblBfOI this purpose is fused quartz.. When such a material is used for the screen 16 the filament 19 inclosed by the screen 16, is thoroughly protectedfromin"- jury for an indefinite period without matetially interfering with its action in starting the rectifier arcs.

In Figs. 1 and 2 I have represented. the startin filament as being coiled into a small but I find it desirable in many instances to coil the filament into such a form that its'spires lie,.within an. imaginary surface either spherical, parabolic. or the like, so as to concentrate the'efi'ective rays given off on the surface of the cathode. Such an arrangement of the filament I have indicated at 20 in Fig. 3, and in this case the various spires scription that various 'modificationso of the filament are arran ed spherically and Tie cathode 22 that the rays from the filament, or a large ortion of them come to a focus at or near t e surface of the cathode. The. starting action is 1 thus accentuated. In connection with the filament 20 a shield, such as 21, of glass, metal or the like, may also be employed or, if de- I sired, a closed shield such as 16 in Fig. 2, 1 may be used.

The filaments shown in Figs. 2 and 3 may be excited from the same current source as that which supplies the rectifier, in which 1 case each filament will be connected between the mercury electrode. or cathode and one of the anodes, as shown in the drawings. The filament may, if desired, be excited from an independent source of current, as in Fig. 1.

It will be evident from the foregoing denvention may be employed without departing from the spirit thereof, for which reason not wish to be limited to the exact details shown and described.

What I claim as new, and desire to secure by Letters Patent of the United States, is, I 1; The combination of 'an evacuated'envelo or tube, electrodes therein one at least of w lich is of mercury, a starting conductor located in prox1m1ty-to the mercury elec-'- trode, and means for protecting the conductor from the washing or scourlng action of mercury in said tube. I i T 2. The combination of'an evacuated envelo or tube, electrodes therein one at least of w ich is of mercury, a conductor presenting a surface of oxid arranged in proxlmity to the mercury electrode for producing an arc therefrom, and a rotective screen or en'- velop for said com uctor formed of a mate rial pervious to are starting radiations from said conductor.

3. The combination of an hermetically sealed envelop or tube, electrodes therein,-a starting conductor having a surface of oxid, and a protecting starting conductor.

. 4. The combination of an hermetically sealed envelop or tube,electrodes therein one at least of which is of vvaporizable material, a

screen or shield for said starting conductor in proximity-to the vaporizable electrode and having a surface of oxid, and a protect ng screen or shield for sald startm conductor.

In witness whereof, I have hereunto set my hand this 10th day ,of October, 1907.

. OSIAS O. KRUH.

Witnesses:

HELEN ORFORD, MARGARET E. WOOLLEY. 

